As populist movements gain strength across the world, attention has turned to Italy, where the government faces pressure from a group known as the Five Star Movement (M5S). Since its inception in 2009, the M5S has risen to become one of the most voted-for parties in Italy. But as the group eyes power, there are questions about whether it would actually be capable of running the country.

The M5S was started in 2009 by comedian Beppe Grillo and web strategist Gianroberto Casaleggio, who had the intuition that the internet could be used as the basis for a new kind of party – one without organisation, money, ideology or headquarters. This encouraged Grillo to use his blog and the social networking site, Meetup.com, to bring people together to campaign on local issues and then field candidates for elections.

The Movement drew initial strength from the twin ideas of a new form of direct democracy and popular disgust with the political elites. Its policies have always been an eclectic mix of the anti-establishment, environmentalist, anti-globalist and eurosceptic, and its supporters have always come from across the political spetrum.

At the 2013 general election, the M5S came from nowhere to become the second most voted for party. Through ups and downs, its poll ratings have stood at around 30% ever since, generally ahead of the centre right and only just behind the centre-left Democratic Party.

The M5s does not seem to have suffered from outcries about how Virginia Raggi, the recently elected mayor of Rome, is running her administration. Nor have allegations that activists have been involved in falsifying signatures on the nomination papers of candidates for elections in Bologna and Palermo dented its progress.

These incidents seem to fly in the face of the M5S’s claim to stand for a new, more honest politics. But people vote for it because it represents something different from a political class in whom vast swathes have virtually no confidence.

The problem with power

Since the M5S draws support from all parts of the political spectrum, the fear among sceptics is that it would sweep the board in a run-off ballot against one of the two biggest political parties in Italy. It would inevitably attract votes from two sources – its own supporters and those opposed to whichever of the parties, the Democratic Party or the centre right, it found itself up against.

However, the profile of M5S activists and supporters casts doubt on whether it would be able to govern effectively if it did win an election. A vote for the M5S is a straightforward protest vote. Despite being united in their desire to shake up the status quo, M5S activists and supporters are divided across the whole range of issues separating left and right. They don’t necessarily share a position on the EU, taxation or migration – in fact M5S voters are more or less split down the middle.

It is doubtful that such a party can remain cohesive when faced with the pressures of governing. The M5S would probably crumble under the weight of the responsibility for making choices that can only benefit some while hurting others.

Beppe Grillo on the campaign trail.EPA/Alessandro Di Meo

Experience both in parliament and in local government confirms that protest parties railing against “the system” are as likely to find themselves being absorbed by it as they are to transform it once in office. Faced with the day-to-day pressure, they are doomed to become a party just like all the others.

Since the 2013 general election, 18 of M5S’s 109 representatives in the Chamber of Deputies (17% of the total) have defected to a different group. Italian parliamentarians are notorious for jumping from one group to another during the course of a legislature – indeed 24% of the house has moved during the current one – but the M5S defectors have clashed with the leadership in a way that reflects what has been a fundamental problem for the movement.

Many have left because they came into conflict with pressures to behave as mere party delegates, rather than as representatives, exercising their own judgement. Grillo claims to espouse the ideology of direct, “bottom-up” democracy but has sought to impose party discipline from the top down. He deals with rebels by threatening to withdraw their right to use the movement’s brand, of which he is the exclusive owner.

So while it’s possible that the movement could do well if the Italian government calls an election in 2017 or 2018, it would find itself uniquely badly placed to withstand the enormous threats to its unity that would come with being in office. The greatest concern would be the market pressures, including capital flight and economic turmoil, that would be caused by the promise of a referendum on euro membership.

And even if it were able to withstand such pressures, it might then find it difficult, if not impossible, to hold such a referendum in the first place. For one thing, the Italian constitution prohibits referendums on the abrogation of laws ratifying international treaties, and the jurisprudence that has developed over the years has extended the prohibition to the laws that give effect to such treaties.

That means that in order to hold a euro membership referendum, it would probably first be necessary to secure a revision of the constitution, and for that to be possible, it would be necessary to win two positive votes in each chamber of parliament at intervals of not less than three months. Without that support, the M5S would almost certainly need to hold a confirmatory referendum for the constitutional revision.

So there might have to be two referendums before an exit from the euro could take place. And then, of course, those referendums would have to be won. In order to achieve that, M5S would have to overcome its current uncertainty about what it would replace euro membership with. And it would have to find a way of persuading the 67% of respondents who currently say they favour continued membership.

Of course, we live in rapidly changing times. But if forced to place a bet on it, I would put my money on there not being a euro exit any time soon – or at least not one engineered by the M5S.